Fabrication of butyrylcholinesterase sensor using polyurethane-based ion-selective membranes

A simple method of enzyme immobilization was investigated which is useful f or fabrication of enzyme sensors based on polymeric ion-selective membranes . The enzyme membrane was built by coating a thin hydrophilic polyurethane (HPU) film directly mixed with an enzyme over an underlying polyurethane (P U)-based ion-selective membrane. This highly simple method of enzyme immobi lization was applied to the fabrication of a potentiometric butyrylcholines terase-based biosensor for the determination of organophosphorus pesticides . The enzyme was well entrapped within the HPU film and the intrinsic poten tiometric response of the underlying ion-selective PU membrane was not infl uenced significantly by the outer HPU/enzyme membrane. The enzyme electrode was optimized by changing systematically the composition of the enzyme mem brane to evaluate the effect of the changes on sensor response. The sensor was successfully applied to the analysis of paraoxon, an organophosphorus p esticide. (C) 1999 Elsevier Science S.A. All rights reserved.